Hi Marek,
On 02.09.2015 12:27, Marek Vasut wrote:
> On Tuesday, September 01, 2015 at 02:32:26 PM, Jian Luo wrote:
>> Hi Marek,
>
> Hi!
>
>> On 01.09.2015 14:03, Marek Vasut wrote:
>> > On Tuesday, September 01, 2015 at 01:49:43 PM, Jian Luo wrote:
>> ----snip----
>>
>> >> What about calling socfpga_sdram_apply_static_cfg() direct in
>> >> socfpga_load() in drivers/fpga/socfpga.c to make it generic?
>> >
>> > Which code exactly do you refer to ?
>>
>> I mean something like this.
>>
>> diff --git a/drivers/fpga/socfpga.c b/drivers/fpga/socfpga.c
>> index 4448250..d0f67f6 100644
>> --- a/drivers/fpga/socfpga.c
>> +++ b/drivers/fpga/socfpga.c
>> @@ -300,5 +300,12 @@ int socfpga_load(Altera_desc *desc, const void
>> *rbf_data, size_t rbf_size)
>> return status;
>>
>> /* Ensure the FPGA entering user mode */
>> - return fpgamgr_program_poll_usermode();
>> + status = fpgamgr_program_poll_usermode();
>> + if (status)
>> + return status;
>> +
>> + /* Latch FPGA2SDRAM bridge configuration */
>> + socfpga_sdram_apply_static_cfg();
>> +
>> + return 0;
>> }
>>
>> >> socfpga_load() already did step 1 and 2.
>> >> Is there any side effect when fpga2sdram bridge is not used?
>> >
>> > The idea is to keep the FPGA programming code and the code which
>> > controls the bridges separate. The reason for that is that you
can have
>> > content in the FPGA which is running completely independent of
the HPS
>> > software. You don't always need to enable the bridges.
>>
>> No, it's the other way around here.
>> socfpga_load() runs eventually when command "fpga load" is called.
>> So when I explicitly use "fpga load" command, the old FPGA program is
>> expected to stop running, right?
>
> Right
>
>> And I don't want to enable the bridge here, just to latch the SDRAM
>> configuration.
>
> So what you want to do is "bridge disable ; fpga load ... ; bridge
enable",
> isn't that the correct sequence ? I might be missing something
though, sorry.
No, you are right. Sorry, I didn't think it through.
My original thought was, that "fpga load" should not depend on "bridge e/d"
regardless of how fpga2sdram is configured. Now I think the dependency
is a bad idea.
Sorry for the confusion.
>
>> > The FPGA2SDRAM bridge (or, more like fpga2hps bridge) is used for
stuff
>> > like framebuffers implemented in the FPGA, so that the FPGA can fetch
>> > data from the SDRAM.
>> >
>> > Best regards,
>> > Marek Vasut
>>
>> Best regards,
>>
>> Jian Luo
>
> Best regards,
> Marek Vasut
Best regards,
Jian Luo
_______________________________________________
U-Boot mailing list
[email protected]
http://lists.denx.de/mailman/listinfo/u-boot
